/**
 * @author aleeper / http://adamleeper.com/
 * @author mrdoob / http://mrdoob.com/
 * @author gero3 / https://github.com/gero3
 * @author Mugen87 / https://github.com/Mugen87
 *
 * Description: A THREE loader for STL ASCII files, as created by Solidworks and other CAD programs.
 *
 * Supports both binary and ASCII encoded files, with automatic detection of type.
 *
 * The loader returns a non-indexed buffer geometry.
 *
 * Limitations:
 *  Binary decoding supports "Magics" color format (http://en.wikipedia.org/wiki/STL_(file_format)#Color_in_binary_STL).
 *  There is perhaps some question as to how valid it is to always assume little-endian-ness.
 *  ASCII decoding assumes file is UTF-8.
 *
 * Usage:
 *  var loader = new THREE.STLLoader();
 *  loader.load( './models/stl/slotted_disk.stl', function ( geometry ) {
 *    scene.add( new THREE.Mesh( geometry ) );
 *  });
 *
 * For binary STLs geometry might contain colors for vertices. To use it:
 *  // use the same code to load STL as above
 *  if (geometry.hasColors) {
 *    material = new THREE.MeshPhongMaterial({ opacity: geometry.alpha, vertexColors: THREE.VertexColors });
 *  } else { .... }
 *  var mesh = new THREE.Mesh( geometry, material );
 */

import THREE from './core'

THREE.STLLoader = function (manager) {

  this.manager = (manager !== undefined) ? manager : THREE.DefaultLoadingManager;

};

THREE.STLLoader.prototype = {

  constructor: THREE.STLLoader,

  load: function (url, onLoad, onProgress, onError) {

    var scope = this;

    var loader = new THREE.FileLoader(scope.manager);
    loader.setResponseType('arraybuffer');
    loader.load(url, function (text) {

      onLoad(scope.parse(text));

    }, onProgress, onError);

  },

  parse: function (data) {

    function isBinary(data) {

      var expect, face_size, n_faces, reader;
      reader = new DataView(data);
      face_size = (32 / 8 * 3) + ((32 / 8 * 3) * 3) + (16 / 8);
      n_faces = reader.getUint32(80, true);
      expect = 80 + (32 / 8) + (n_faces * face_size);

      if (expect === reader.byteLength) {

        return true;

      }

      // An ASCII STL data must begin with 'solid ' as the first six bytes.
      // However, ASCII STLs lacking the SPACE after the 'd' are known to be
      // plentiful.  So, check the first 5 bytes for 'solid'.

      // US-ASCII ordinal values for 's', 'o', 'l', 'i', 'd'

      var solid = [115, 111, 108, 105, 100];

      for (var i = 0; i < 5; i++) {

        // If solid[ i ] does not match the i-th byte, then it is not an
        // ASCII STL; hence, it is binary and return true.

        if (solid[i] != reader.getUint8(i, false)) return true;

      }

      // First 5 bytes read "solid"; declare it to be an ASCII STL

      return false;

    }

    function parseBinary(data) {

      var reader = new DataView(data);
      var faces = reader.getUint32(80, true);

      var r, g, b, hasColors = false, colors;
      var defaultR, defaultG, defaultB, alpha;

      // process STL header
      // check for default color in header ("COLOR=rgba" sequence).

      for (var index = 0; index < 80 - 10; index++) {

        if ((reader.getUint32(index, false) == 0x434F4C4F /*COLO*/) &&
          (reader.getUint8(index + 4) == 0x52 /*'R'*/) &&
          (reader.getUint8(index + 5) == 0x3D /*'='*/)) {

          hasColors = true;
          colors = [];

          defaultR = reader.getUint8(index + 6) / 255;
          defaultG = reader.getUint8(index + 7) / 255;
          defaultB = reader.getUint8(index + 8) / 255;
          alpha = reader.getUint8(index + 9) / 255;

        }

      }

      var dataOffset = 84;
      var faceLength = 12 * 4 + 2;

      var geometry = new THREE.BufferGeometry();

      var vertices = [];
      var normals = [];

      for (var face = 0; face < faces; face++) {

        var start = dataOffset + face * faceLength;
        var normalX = reader.getFloat32(start, true);
        var normalY = reader.getFloat32(start + 4, true);
        var normalZ = reader.getFloat32(start + 8, true);

        if (hasColors) {

          var packedColor = reader.getUint16(start + 48, true);

          if ((packedColor & 0x8000) === 0) {

            // facet has its own unique color

            r = (packedColor & 0x1F) / 31;
            g = ((packedColor >> 5) & 0x1F) / 31;
            b = ((packedColor >> 10) & 0x1F) / 31;

          } else {

            r = defaultR;
            g = defaultG;
            b = defaultB;

          }

        }

        for (var i = 1; i <= 3; i++) {

          var vertexstart = start + i * 12;

          vertices.push(reader.getFloat32(vertexstart, true));
          vertices.push(reader.getFloat32(vertexstart + 4, true));
          vertices.push(reader.getFloat32(vertexstart + 8, true));

          normals.push(normalX, normalY, normalZ);

          if (hasColors) {

            colors.push(r, g, b);

          }

        }

      }

      geometry.addAttribute('position', new THREE.BufferAttribute(new Float32Array(vertices), 3));
      geometry.addAttribute('normal', new THREE.BufferAttribute(new Float32Array(normals), 3));

      if (hasColors) {

        geometry.addAttribute('color', new THREE.BufferAttribute(new Float32Array(colors), 3));
        geometry.hasColors = true;
        geometry.alpha = alpha;

      }

      return geometry;

    }

    function parseASCII(data) {

      var geometry = new THREE.BufferGeometry();
      var patternFace = /facet([\s\S]*?)endfacet/g;
      var faceCounter = 0;

      var patternFloat = /[\s]+([+-]?(?:\d+.\d+|\d+.|\d+|.\d+)(?:[eE][+-]?\d+)?)/.source;
      var patternVertex = new RegExp('vertex' + patternFloat + patternFloat + patternFloat, 'g');
      var patternNormal = new RegExp('normal' + patternFloat + patternFloat + patternFloat, 'g');

      var vertices = [];
      var normals = [];

      var normal = new THREE.Vector3();

      var result;

      while ((result = patternFace.exec(data)) !== null) {

        var vertexCountPerFace = 0;
        var normalCountPerFace = 0;

        var text = result[0];

        while ((result = patternNormal.exec(text)) !== null) {

          normal.x = parseFloat(result[1]);
          normal.y = parseFloat(result[2]);
          normal.z = parseFloat(result[3]);
          normalCountPerFace++;

        }

        while ((result = patternVertex.exec(text)) !== null) {

          vertices.push(parseFloat(result[1]), parseFloat(result[2]), parseFloat(result[3]));
          normals.push(normal.x, normal.y, normal.z);
          vertexCountPerFace++;

        }

        // every face have to own ONE valid normal

        if (normalCountPerFace !== 1) {

          console.error('THREE.STLLoader: Something isn\'t right with the normal of face number ' + faceCounter);

        }

        // each face have to own THREE valid vertices

        if (vertexCountPerFace !== 3) {

          console.error('THREE.STLLoader: Something isn\'t right with the vertices of face number ' + faceCounter);

        }

        faceCounter++;

      }

      geometry.addAttribute('position', new THREE.Float32BufferAttribute(vertices, 3));
      geometry.addAttribute('normal', new THREE.Float32BufferAttribute(normals, 3));

      return geometry;

    }

    function ensureString(buffer) {

      if (typeof buffer !== 'string') {

        var array_buffer = new Uint8Array(buffer);

        if (window.TextDecoder !== undefined) {

          return new TextDecoder().decode(array_buffer);

        }

        var str = '';

        for (var i = 0, il = buffer.byteLength; i < il; i++) {

          str += String.fromCharCode(array_buffer[i]); // implicitly assumes little-endian

        }

        return str;

      } else {

        return buffer;

      }

    }

    function ensureBinary(buffer) {

      if (typeof buffer === 'string') {

        var array_buffer = new Uint8Array(buffer.length);
        for (var i = 0; i < buffer.length; i++) {

          array_buffer[i] = buffer.charCodeAt(i) & 0xff; // implicitly assumes little-endian

        }
        return array_buffer.buffer || array_buffer;

      } else {

        return buffer;

      }

    }

    // start

    var binData = ensureBinary(data);

    return isBinary(binData) ? parseBinary(binData) : parseASCII(ensureString(data));

  }

};